Is Idaho tap water hard or soft?
Yes, mostly. 67 % of the 9 cities with published data in Idaho have hard or very hard water (over 120 mg/L). The median is 9.4 gpg, from 2.1 gpg in Lewiston to 18 gpg in Chubbuck.
We have published hardness data for 9 cities in Idaho. The median is 9.4 gpg; the hardest water is in Chubbuck (18 gpg), the softest in Lewiston (2.1 gpg).
67 % of these cities have hard or very hard water (over 120 mg/L).
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Cities in Idaho, hardest first
| gpg | mg/L | ||
|---|---|---|---|
| Chubbuck | 18 | 308 | very hard |
| Twin Falls | 16 | 274 | very hard |
| Jerome | 11.9 | 203 | very hard |
| Garden City | 9.9 | 170 | hard |
| Meridian | 9.4 | 161 | hard |
| Coeur d'Alene | 8.2 | 141 | hard |
| Moscow | 6.4 | 110 | moderately hard |
| Star | 5.4 | 92 | moderately hard |
| Lewiston | 2.1 | 36 | soft |
FAQ
Is Idaho water hard or soft?
Yes, mostly. 67 % of the 9 cities we cover have hard or very hard water; the median is 9.4 gpg.
Which city in Idaho has the hardest water?
Chubbuck, at 18 gpg, has the hardest water of the 9 cities with published data.
Which city in Idaho has the softest water?
Lewiston, at 2.1 gpg, has the softest water of the 9 cities with published data.
Do I need a water softener in Idaho?
Above about 120 mg/L (7 gpg) scale builds up in water heaters, kettles and dishwashers, and a softener or at least regular descaling pays off. Look up your own city in the table: in Idaho the values range from 2.1 gpg to 18 gpg.